University of Vermont Extension System
Department of Plant and Soil Science

Allergies and Gardening                     OH 71

Leonard P. Perry, Extension Professor

If youíre like one in six Americans, you get some sort of seasonal allergies each year. If youíre a gardener, this doesnít mean you have to suffer. Or you donít have to give up gardening during part of the season. Or you donít have to convert your landscape into silk flowers, gravel beds and garden gnomes or plastic flamingos! Perhaps changing some gardening practices, or some of your plants, may be all thatís needed to lessen the grief.

Most see the yellow pollen on their car in spring or summer and think, thatís it! But this relatively big, showy pollen you see from trees and flowers really isnít the culprit. Itís the microscopic pollen you donít see that causes allergies. This can be from deciduous trees in the spring such as oak, elm, birch, maple, ash, alder, some pines, box elder, and willow. The hardwoods especially are the culprits. Other trees, especially in warmer parts of the country (whether you live there, or may be traveling there to visit gardens) include cedar, cottonwood, hickory, mulberry, olive, palm, and pecan.

Trees with showy flowers, just as with flowers, tend to be pollinated by bees, butterflies or similar, so have larger pollen which doesnít blow around and cause allergies. Examples of low or no allergen trees include many of the fruit trees such as apples, crabapples, cherries, pear, plum and others in warmer climates such as dogwoods and magnolias.

Shrubs to avoid include many junipers, and in warmer climates cypress and privet. Hydrangea, azaleas and viburnum are okay, as are in warmer climates the boxwood and hibiscus.

In his recent book Allergy-free Gardening, author Thomas Ogren attributes many of our allergies to recent changes in our landscapes, particularly the planting of male trees and shrubs. We often do this to avoid messy fruit from female trees, but end up as a result with more pollen. He even advocates sex-changes in treesógrafting a female top onto existing trunks of male trees. He has also developed and advocates using the Ogren Plant Allergy Scale, rating plants from 1 (low) to 10 (high) for pollen and allergies.

As with the woody plants, those herbaceous plants with showy flowers are generally okay and include many such as daffodil, tulip, daisies, geranium impatiens, iris, lilies, pansies, petunias, roses, sunflowers, zinnias and many more. Some flowers with strong scents may also aggravate allergies, even if they normally have larger pollen.

Most lawn grasses donít cause problems as they are mowed often and not allowed to set seed. But they can cause problems if allowed to go to seed including perennial rye, fescue, and bermuda in warmer climates.

Of course weeds are often the most allergenic plants. One ragweed plant can produce up to one billion pollen grains, and they have been tracked over 400 miles away! Others include pigweed and Russian thistle. A couple perennials are falsely accused of allergies, as they bloom at the same time as ragweed. You see the goldenrod and helenís flower (alias "sneezeweed") and think these are the enemy, while it is really the ragweed lurking in the background.

Plants and pollen are the only allergy producers in the garden. Molds cause allergies in some people and children, and can be produced from composts and decomposing bark mulch. If you or family members are allergic to molds, consider buying finished compost, not making it at home. And you may want to replace bark mulch, shredded leaves, cocoa hulls or similar organic material with pebbles or even just clean cultivation. I prefer to quickly get plants established, so they cover the bed and leave no room or light for weed seeds to germinate (well, at least fewer seeds).

Here are 13 gardening practices you might change to reduce sneezing, itchy and runny noses and still be able to garden:

For more information, you may wish to consult the book Allergy-free Gardening by Thomas Ogren. Websites with useful information are those of the American Lung Association, the American Academy of Allergy, Asthma and Immunology, and the Intellicast weather site among others. These any more can be found through a search on an internet search engine such as Google. Also keep watch in your local daily broadcast and print media during the season for pollen counts, and garden when the counts are lower.



Return to Perry's Perennial Consumer Page

Issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, in cooperation with the United States Department of Agriculture. Lawrence Forcier, Director, UVM Extension System, Burlington, Vermont. University of Vermont Extension System and U.S. Department of Agriculture cooperating, offer education and employment to everyone, without regard to race, color, national origin, sex, religion, age, disability, political beliefs, and marital or familial status.

Last reviewed 2/02